With the rapid development of display technology, touch screen panels have been gradually widespread in people's lives. Currently, in view of the structures, the touch screen panels can be divided into: add-on mode touch panels, on-cell touch panels and in-cell touch panels. The add-on mode touch panel needs to separately produce a touch screen and a liquid crystal display (LCD) which are hence bonded together to form an LCD with touch function. The add-on mode touch panel has the defects of high manufacturing cost, low light transmittance and thick modules. The in-cell touch panel allows touch electrodes of a touch screen to be embedded into an LCD, not only can reduce the overall thickness of modules but also can greatly reduce the manufacturing cost of the touch panel, and is favored by the major panel manufacturers.
Currently, the in-cell touch panel detects a finger touch position in accordance with the mutual-capacitance or self-capacitance principle. A plurality of self-capacitance electrodes arranged in the same layer and insulated from each other are disposed in the touch panel in accordance with the self-capacitance principle. When a human body does not touch the screen, the capacitance of the self-capacitance electrode is a fixed value. When a human body touches the screen, the capacitance of corresponding self-capacitance electrode is at a value of a fixed value plus the body capacitance. A touch detection chip can determine the touch position by the detection of the capacitance variation of the self-capacitance electrode in a touch period. As the body capacitance can act on the entire self-capacitance, compared with the case that the body capacitance can only act on the projected capacitance in mutual capacitance, the touch variation caused by the fact that the human body touches the screen will be greater than that of a touch panel produced in accordance with the mutual-capacitance principle. Compared with a mutual-capacitance touch panel, a self-capacitance touch panel can effectively improve the signal-to-noise ratio of touch and hence improve the accuracy of touch sensing.
In the structural design of the capacitive in-cell touch panel, extra layers must be added in a display panel to form corresponding electrodes and the like, so that new processes must be added in the process of manufacturing the panel. Therefore, the manufacturing cost can be increased and the productivity cannot be effectively improved.